The U.S. Army Pueblo Chemical Depot (PCD) is located in southeastern Colorado, encompassing approximately 23,000 acres. The depot’s mission is the safe, secure storage of mustard agent in projectiles and mortars, while protecting the environment, workforce and surrounding communities. The obsolete chemical weapons, stored and monitored at the depot since the 1950s, were destroyed in compliance with the Chemical Weapons Convention. This chemical weapons destruction program extensively involves the local community, in addition to state and federal regulators.
Pueblo Chemical Agent-Destruction Pilot Plant
Located within the current boundaries of the depot, the Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) includes a variety of facilities for purposes including agent processing, energetic processing, control and storage, munitions storage, biotreatment, entry control, utility, laboratory, personnel maintenance and other support tasks. The Bechtel Pueblo Team (BPT) was awarded the systems contract to design, construct, systemize, pilot test, operate and close the facilities.
The Program Executive Office, Assembled Chemical Weapons Alternatives, known as PEO ACWA, was responsible for completing destruction operations by the Chemical Weapons Convention treaty commitment of Sept. 30, 2023. U.S. public law mandates stockpile destruction by Dec. 31, 2023.
Technology
On July 16, 2002, Department of Defense officials selected neutralization followed by biotreatment as the disposal technology used at PCD. Neutralization followed by biotreatment used warm water to neutralize the chemical agent, effectively destroying the mustard agent molecules. The resulting hydrolysate is mostly water and thiodiglycol, a common industrial chemical that is readily biodegradable. Ordinary sewage treatment bacteria, or microbes, consume the organics in the hydrolysate. Besides being a common phenomenon in nature, the science of using microbes to help dispose of hazardous waste has existed for decades. Sewage treatment facilities across the country use microbes every day to help break down raw sewage.
Some munitions could not be easily processed in the main destruction plant. These munitions include those that have leaked in the past and were overpacked, as well as rejects whose condition did not allow for automated processing. These munitions were safely destroyed at PCAPP’s Static Detonation Chamber (SDC) complex along with 4.2-inch mortar rounds. Improved Cavity Access Machines (ICAMs) were developed and installed in the main plant to allow for the safe, automated destruction of a portion of the 4.2-inch mortar rounds.
Public Outreach
The Pueblo Chemical Stockpile Outreach Office and the Pueblo Chemical Depot Public Affairs Office keep the community informed of issues regarding chemical weapons destruction. The offices respond to inquiries, provide information materials and coordinate guest speakers for a variety of different civic groups and organizations. The offices work closely with the Army, state regulatory agencies and local and state emergency preparedness authorities to create a comprehensive public involvement and outreach program.